Indoor antenna for television reception



Oct. 24, 1961 P. A. BERNFELD 3,

INDOOR ANTENNA FOR TELEVISION RECEPTION Filed June 28, 1960 2Sheets-Sheet 1 INVENTOR. PHILIP ABRAHAM BERNFELD gmw A TTOP/VFY Oct. 24,1961 P. A. BERNFELD INDOOR ANTENNA FOR TELEVISION RECEPTION 2Sheets-Sheet 2 Fil ed June 28, 1960 INVENITOR. PHILIP ABRA HAM BERNFELD"LOOP ARRAY SELECTOR POSITION P2 P3 P4 P5 ATTOPA/T) 3,005,982 INDOORANTENNA FOR TELEVESTON RECEPTION Philip Abraham Bernfeld, 15314 73rdAve.,

Flushing, N .Y. Filed June 28, 1960, Ser. No. 39,280 Claims. (Cl.343-724) with a plurality of vertically disposed loops mounted on a baseand interconnected via adjustable switch means in any of a plurality ofpredetermined arrays.

A further object is to provide a novel assembly of Vertical loops andhorizontal dipoles in an indoor antenna.

Another object is to provide an assembly of loops and dipoles in anindoor antenna in which the loops and dipoles can be serially connectedor individually connected to an antenna lead-in transmission line whileunconnected loops and dipoles serve as reflectors to shield the signalreceiving members against spurious signals.

For further comprehension of the invention, and of the objects andadvantages thereof, reference will be had to the following descriptionand accompanying drawings, and to the appended claims in which thevarious novel features of the invention are more particularly set forth.

In the accompanying drawings forming a material part of this disclosure:

FIG. 1 is a top plan view of an antenna assembly em bodying theinvention.

FIG. 2 is a front elevational view of the antenna assembly.

FIG. 3 is a vertical cross-sectional view taken on line 33 of FIG. 1.

FIG. 4 is a schematic diagram of the antenna assembly.

FIG. 5 is a chart identifying and listing the several arrays of loops inthe different positions of the selector switch.

FIGS. 6 and 7 are cross sections of rod and tubing useful in forming theantenna.

Referring to FIGS. l-3, there is shown a rectangular base 10 providing aplatform 12 on which is mounted a plurality of generally circularlycurved conductive, tubular loops V1-V4 open at the bottom. The loopshave a vertical diametral length substantially equal to one quarter ofthe wavelength of the center frequency of the broadcast band to whichthe antenna is responsive. The ends of the several loops are joined byhorizontally disposed conductive, tubular links III-H3 which are centertapped at T1-T3; see FIGS. 3 and 4.

The taps T1-T3 pass through openings in the platform 12 into the cavitydefined by platform 12 and walls 15-18 of the base. Loops V1 and V4 haveends connected to horizontal unipoles HD4A and HD4B. The ends of theseunipoles are joined to a resistor 20. These ends terminate in taps T4Aand T4B;

On front wall 15 of the base is a selector switch 22 controlled by aknob 24 marked with an index mark 25 to indicate its switch position.Eight switch positions P1-P8 are provided but more or less switchpositions may be employed if desired.

The switch 22 includes an insulated disk 26 on which are lugs 28 towhich are connected Wires 30. The wires are preferably conductorsshielded by braided wire or center conductors of coaxial cables. Thelugs are arranged in eight pairs and are connected to an inner circulararray of spaced fixed contacts C1-C8 and to an outer circular array ofspaced fixed contacts C1C8 at switch positions P1P8, respectively; seeFIG. 4. The knob 24 is mounted on an insulated shaft 23 which carriestwo spaced conductive rings 29, 31. Ring 29 has a radial arm 32 whichmakes contact with the inner contacts C1-C8 in turn at the severalswitch positions. Arm 34 is carried radially by ring 31 and is spacedangularly from arm 32 a fixed distance to that arm 34 contacting one ofthe outer contacts C1'C8 of a pair, while arm 32 is contacting the innercontact C1-C8 of the same pair. Transmission line 36 has conductors 38,40 terminating in wiper contacts 39, 41 for making contact with rings 31and 29, respectively, in all positions thereof.

FIG. 5 lists in chart form the array of loops to which line conductors38, 49 are connected at each of the positions P1-P8 of the selectorswitch. At positions P1, P2, P4 and P6, individual loops V1, V2, V3 andV4 are connected to the external transmission line. At positions P2, P5and P8, two loops V1, V2; V2, V3; and V1, V4 are serially connected. Atswitch position P7, three loops V1, V2 and V3 are serially connected.

Thus, by setting the switch 22 to each position in turn, it is possibleto orient the antenna for optimum reception of signals emitted bystations broadcasting from any of several directions.

When any one loop or group of loops are connected to the line 36, theremaining unconnected loops serve as active reflectors to stop spurioussignal reflections approaching from directions removed from thedirection of approach of the desired signals.

The antenna assembly is simple to operate, requiring only a singlecontrol knob. The user will tune the antenna by rotating the knob untiloptimum reception is noted at the receiver (not shown) connected to thetransmission line.

The horizontal links in the several arrays increase the gain of theantenna by picking up components of signals arriving from directionsother than horizontal. They therefore constitute in effect horizontaldipoles in series with vertical loops. Since the loops are primarilyinductive in nature while the horizontal links are primarilycapacitative, they may constitute tuned resonant circuits which serve toresonate and intensity the amplitudes of the received signals.

The several links and loops may be formed from a single length ofaluminum or other metal tubing bent to the form shown in the drawings.The tubing may be coated with cooper, cadmium, silver, or other highlyconductive metal to improve reception by reducing high frequency energylosses. As an alternative the loop may be formed of low-loss plastic rod50 or tubing 52 coated with a highly conductive metal coating 51 or 53as indicated in FIGS. 6 and 7, respectively.

While I have illustrated and described the preferred embodiment of myinvention, it is to be understood that I do not limit myself to theprecise construction herein disclosed and that various changes andmodifications may be made within the scope of the invention as definedin the appended claims.

Having thus described my invention, what I claim as new, and desire tosecure by United States Letters Patent 1. An antenna for reception ofhigh frequency broadcast signals, comprising a base, a plurality ofconductive loops disposed in vertical planes at right angles to eachother on said base, horizontal links connecting ends of the loops,switch means having a plurality of switch positions, said horizontallinks having taps connected to said switch means at the severalpositions thereof, and a transmission line connected to rotatablecontacts of said switch means, whereby selected ones of said loops andlinks are connected to said line at each position of the switch whilethe other loops and links serve as reflectors shielding the selectedloops and links from spurious radiated signals.

2. An antenna for reception of high frequency broadcast signals,comprising a base including a raised platform and side walls defining acavity therewith, a rod having an external electrically conductivesurface, said rod being formed to define four loops and four dipolelinks, said loops being disposed in vertical planes at right angles toeach other on said platform, said links being disposed horizontally andhaving taps extending through said platform into said cavity, multipleposition switch means mounted on one of said walls and having spacedcontacts connected to said taps, said switch means having rotatablecontacts, and a transmission line having wipers connected to saidrotatable contacts whereby selected ones of said loops and links areconnected to said transmission line at each of the positions of saidswitch means.

3. An antenna for reception of high frequency broadcast signals,comprising a base including a raised platform and side walls defining acavity therewith, a rod having an external electrically conductivesurface, said rod being formed to define four loops and four dipolelinks, said loops being disposed in vertical planes at right angles toeach other on said platform, said links being disposed horizontally andhaving taps extending through said platform into said cavity, multipleposition switch means mounted on one of said walls and having spacedcontacts connected to said taps, said switch means having rotatablecontacts, and a transmission line having wipers connected to saidrotatable contacts whereby selected ones of said loops and links areconnected to said transmission line at each of the positions of saidswitch means, said rod being formed of low-loss material coated withhighly conductive metal.

4. An antenna for reception of high frequency broadcast signals,comprising a base including a raised platform and side walls defining acavity therewith, a rod having an external electrically conductivesurface, said rod being formed to define four loops and four dipolelinks, said loops being disposed in vertical planes at right angles toeach other on said platform, said links being disposed horizontally andhaving taps extending through said platform into said cavity, multipleposition switch means mounted on one of said walls and having spacedcontacts connected to said taps, said switch means having rotatablecontacts, and a transmission line having Wipers connected to saidrotatable contacts whereby selected ones of said loops and links areconnected to said transmission line at each of the positions of saidswitch means, said rod being a plastic tube coated with highlyconductive metal.

5. An antenna for reception of high frequency broadcast signals,comprising a base including a raised platform and side walls defining acavity therewith, a rod having an external electrically conductivesurface, said rod being formed to define four loops and four dipolelinks, said loops being disposed in vertical planes at right angles toeach other on said platform, said links being disposed horizontally andhaving taps extending through said platform into said cavity, multipleposition switch means mounted on one of said walls and having spacedcontacts connected to said taps, said switch means having rotatablecontacts, and a transmission line having wipers connected to saidrotatable contacts whereby selected ones of said loops and links areconnected to said transmission line at each of the positions of saidswitch means, said rod being a metal tube.

6. An antenna assembly comprising an array of conductive loops disposedin vertical planes at angles to each other, successive loops beingconnected by horizontal curved links center-tapped to define dipoles,two of said loops terminating in taps connected by a resistor, amultiple position switch having fixed contacts connected to taps of thelinks, rotatable contacts disposed to contact the fixed contacts at eachposition of the switch, and a transmission line having terminals makingwiping contact with the rotatable contacts for selectively connectingindividual ones of said loops to the transmission line at certainpositions of the switch and for selectively connecting groups ofserially connected loops and links in others of the switch positions.

7. An antenna assembly comprising an array of conductive loops disposedin vertical planes at angles to each other, successive loops beingconnected by horizontal curved links center-tapped to define dipoles,two of said loops terminating in taps connected by a resistor, amultiple position switch having fixed contacts connected to taps of thelinks, rotatable contacts disposed to contact the fixed contacts at eachposition of the switch, and a transmission line having terminals makingwiping contact with the rotatable contacts for selectively connectingindividual ones of said loops to the transmission line at certainpositions of the switch and for selectively connecting groups ofserially connected loops and links in others of the switch positions,there being four of said loops and four of said dipoles in planes insaid array at right angles to each other.

8. An antenna assembly comprising an array of conductive loops disposedin vertical planes at angles to each other, successive loops beingconnected by horizontal curved links center-tapped to define dipoles,two of said loops terminating in taps connected by a resistor, amultiple position switch having fixed contacts connected to taps or thelinks, rotatable contacts disposed to contact the fixed contacts at eachposition of the switch, and a transmission line having terminals makingwiping contact with the rotatable contacts for selectively connectingindividual ones of said loops to the transmission line at certainpositions of the switch and for selectively connecting groups ofserially connected loops and links in others of the switch positions,there being four of said loops and four of said dipoles in planes insaid array at right angles to each other, said loops and links beingformed by a single piece of bent conductive material.

9. An antenna assembly comprising an array of conduc- *tive loopsdisposed in vertical planes at angles to each other, successive loopsbeing connected by horizontal curved links center-tapped to definedipoles, two of said loops terminating in taps connected by a resistor,a multiple position switch having fixed contacts connected to taps ofthe links, rotatable contacts disposed to contact the fixed contacts ateach position of the switch, and a transmission line having terminalsmaking wiping contact with the rotatable contacts for selectivelyconnecting individual ones of said loops to the transmission line atcertain positions of the switch and for selectively connecting groups ofserially connected loops and links in others of the switch positions,said loops and links being formed by a single piece of bent and shapedplastic rod coated with metal.

10. An antenna assembly comprising an array of conductive loops disposedin vertical planes at angles to each other, successive loops beingconnected by horizontal curved links center-tapped to define dipoles,two of said loops terminating in taps connected by a resistor, amultiple position switch having fixed contacts connected to taps of thelinks, rotatable contacts disposed to contact the fixed contacts at eachposition of the switch, and a transmission line having terminals makingwiping contact with the rotatable contacts for selectively connectingindividual ones of said loops to the transmission line at certainpositions of the switch and for selectively connecting groups ofserially connected loops and links in others of the switch positions,said array being formed by a single piece of metal tubing bent andshaped to form said loops and links.

No references cited.

